The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. To enhance the performance of ICs, strained source/drain regions may be used. However, a single IC chip may have different types of transistors. These different types of transistors may need to be optimized differently, which means the strained source/drain structures for these different types of transistors may need to be configured and implemented differently. However, current methods of fabricating strained source/drain structures do not take into these different optimization needs into account.
Therefore, while existing methods of fabricating strained source/drain structures have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect.